1. Field of the Invention
The present invention is directed to improvements in the efficient manufacture of ready-to-wear garments and more particularly relates to improvements in the manufacture of belt loop strips which are sewn to a garment at the waist band for supporting a belt inserted through the loops. Still more particularly, the improvements relate to the simultaneous cutting and sealing of such strips to prevent unsightly fraying of the textile material at the ends.
2. Field of the Prior Art
It is conventional in the garment industry to make belt loops by folding longitudinally a long strip of fabric, usually the same fabric as used for the rest of the garment whether cotton, wool or synthetic, to make a double thickness flat tape with a longitudinal seam centered on one side of the tape. The seam is stitched closed on a specialized sewing machine in long continuous lengths. These lengths of tape are then fed into a second specialized machine designed to cut this tape at a high rate of speed into relatively short strips of suitable length for subsequent sewing to the garment in the form of belt loops. Typically, the ends of these strips are folded under at each end and sewn to the outside of the garment's waistband. The ends of the belt loops in mass manufactured lower cost garments are left unfinished since considerable time and labor would be involved in sewing closed the ends of the belt loop strips. As a result, it is common that after some wear and machine washing of these garments, such as jeans, the ends of the belt loops become frayed and the fabric fiber unravels in unsightly clumps of loose fibers.
The problem of sealing the edges of cut textile fabric has been addressed in the past and various solutions proposed. It is well-known in the industry to seal the edges of textile materials having at least some thermo-plastic fiber content by means of ultrasonic cutting and sealing heads such as for example, are disclosed in U.S. Pat. Nos. 4,610,750 issued to Mango, 4,496,407 to Lowery, Sr. et al., or 4,500,372 issued to Mion. The use of heat sealing and cutting elements is also known as exemplified in U.S. Pat. No. 4,,699,670 to Mims.
The problem of simultaneously cutting and sealing thermoplastic sheets is discussed in U.S. Pat. Nos. 4,767,482 to Diez et al., 4,545,844 issued to Buchanan, and 4,619,102 to Gesinger. Applicant is further aware of U.S. Pat. Nos. 3,828,367 to Bourgeois, 4,244,773 to Siebeck et al., and 4,332,637 to Miller.
The use of ultrasonic cutting heads is not effective with natural fiber fabrics and particularly with heavy cotton denim commonly used in the manufacture of jeans and other low cost garments. Likewise, mere application of heat is ineffective with such fabrics since typically they do not contain thermoplastic fibers.
Zimmerman et al., U.S. Pat. No. 4,426,241 shows a belt loop fabricating machine which cuts and seals loops of fabric by using a separate blade element and an ultrasonic cold welding head.
A continuing need exists for a relatively simple and economical but efficient method for simultaneously cutting and sealing belt loop strips made of a variety of textile fibers and particularly natural fibers such as cotton denim.